2 * Copyright (c) 2000 Damien Miller. All rights reserved.
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
14 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
15 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
16 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
17 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
18 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
19 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
20 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
21 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
22 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31 #include "auth-options.h"
37 extern char *__progname;
39 extern int use_privsep;
41 RCSID("$Id: auth-pam.c,v 1.54 2002/07/28 20:24:08 stevesk Exp $");
42 RCSID("$FreeBSD: src/crypto/openssh/auth-pam.c,v 1.2.2.4 2003/02/03 17:31:06 des Exp $");
43 RCSID("$DragonFly: src/crypto/openssh/Attic/auth-pam.c,v 1.2 2003/06/17 04:24:36 dillon Exp $");
45 #define NEW_AUTHTOK_MSG \
46 "Warning: Your password has expired, please change it now."
47 #define NEW_AUTHTOK_MSG_PRIVSEP \
48 "Your password has expired, the session cannot proceed."
50 static int do_pam_conversation(int num_msg, const struct pam_message **msg,
51 struct pam_response **resp, void *appdata_ptr);
53 /* module-local variables */
54 static struct pam_conv conv = {
55 (int (*)())do_pam_conversation,
58 static char *__pam_msg = NULL;
59 static pam_handle_t *__pamh = NULL;
60 static const char *__pampasswd = NULL;
62 /* states for do_pam_conversation() */
63 enum { INITIAL_LOGIN, OTHER } pamstate = INITIAL_LOGIN;
64 /* remember whether pam_acct_mgmt() returned PAM_NEW_AUTHTOK_REQD */
65 static int password_change_required = 0;
66 /* remember whether the last pam_authenticate() succeeded or not */
67 static int was_authenticated = 0;
69 /* Remember what has been initialised */
70 static int session_opened = 0;
71 static int creds_set = 0;
73 /* accessor which allows us to switch conversation structs according to
74 * the authentication method being used */
75 void do_pam_set_conv(struct pam_conv *conv)
77 pam_set_item(__pamh, PAM_CONV, conv);
80 /* start an authentication run */
81 int do_pam_authenticate(int flags)
83 int retval = pam_authenticate(__pamh, flags);
84 was_authenticated = (retval == PAM_SUCCESS);
89 * PAM conversation function.
90 * There are two states this can run in.
92 * INITIAL_LOGIN mode simply feeds the password from the client into
93 * PAM in response to PAM_PROMPT_ECHO_OFF, and collects output
94 * messages with into __pam_msg. This is used during initial
95 * authentication to bypass the normal PAM password prompt.
97 * OTHER mode handles PAM_PROMPT_ECHO_OFF with read_passphrase()
98 * and outputs messages to stderr. This mode is used if pam_chauthtok()
99 * is called to update expired passwords.
101 static int do_pam_conversation(int num_msg, const struct pam_message **msg,
102 struct pam_response **resp, void *appdata_ptr)
104 struct pam_response *reply;
108 /* PAM will free this later */
109 reply = xmalloc(num_msg * sizeof(*reply));
111 for (count = 0; count < num_msg; count++) {
112 if (pamstate == INITIAL_LOGIN) {
114 * We can't use stdio yet, queue messages for
117 switch(PAM_MSG_MEMBER(msg, count, msg_style)) {
118 case PAM_PROMPT_ECHO_ON:
121 case PAM_PROMPT_ECHO_OFF:
122 if (__pampasswd == NULL) {
126 reply[count].resp = xstrdup(__pampasswd);
127 reply[count].resp_retcode = PAM_SUCCESS;
131 if (PAM_MSG_MEMBER(msg, count, msg) != NULL) {
132 message_cat(&__pam_msg,
133 PAM_MSG_MEMBER(msg, count, msg));
135 reply[count].resp = xstrdup("");
136 reply[count].resp_retcode = PAM_SUCCESS;
144 * stdio is connected, so interact directly
146 switch(PAM_MSG_MEMBER(msg, count, msg_style)) {
147 case PAM_PROMPT_ECHO_ON:
148 fputs(PAM_MSG_MEMBER(msg, count, msg), stderr);
149 fgets(buf, sizeof(buf), stdin);
150 reply[count].resp = xstrdup(buf);
151 reply[count].resp_retcode = PAM_SUCCESS;
153 case PAM_PROMPT_ECHO_OFF:
155 read_passphrase(PAM_MSG_MEMBER(msg, count,
156 msg), RP_ALLOW_STDIN);
157 reply[count].resp_retcode = PAM_SUCCESS;
161 if (PAM_MSG_MEMBER(msg, count, msg) != NULL)
162 fprintf(stderr, "%s\n",
163 PAM_MSG_MEMBER(msg, count, msg));
164 reply[count].resp = xstrdup("");
165 reply[count].resp_retcode = PAM_SUCCESS;
179 /* Called at exit to cleanly shutdown PAM */
180 void do_pam_cleanup_proc(void *context)
182 int pam_retval = PAM_SUCCESS;
184 if (__pamh && session_opened) {
185 pam_retval = pam_close_session(__pamh, 0);
186 if (pam_retval != PAM_SUCCESS)
187 log("Cannot close PAM session[%d]: %.200s",
188 pam_retval, PAM_STRERROR(__pamh, pam_retval));
191 if (__pamh && creds_set) {
192 pam_retval = pam_setcred(__pamh, PAM_DELETE_CRED);
193 if (pam_retval != PAM_SUCCESS)
194 debug("Cannot delete credentials[%d]: %.200s",
195 pam_retval, PAM_STRERROR(__pamh, pam_retval));
199 pam_retval = pam_end(__pamh, pam_retval);
200 if (pam_retval != PAM_SUCCESS)
201 log("Cannot release PAM authentication[%d]: %.200s",
202 pam_retval, PAM_STRERROR(__pamh, pam_retval));
206 /* Attempt password authentation using PAM */
207 int auth_pam_password(Authctxt *authctxt, const char *password)
209 extern ServerOptions options;
211 struct passwd *pw = authctxt->pw;
213 do_pam_set_conv(&conv);
215 /* deny if no user. */
218 if (pw->pw_uid == 0 && options.permit_root_login == PERMIT_NO_PASSWD)
220 if (*password == '\0' && options.permit_empty_passwd == 0)
223 __pampasswd = password;
225 pamstate = INITIAL_LOGIN;
226 pam_retval = do_pam_authenticate(
227 options.permit_empty_passwd == 0 ? PAM_DISALLOW_NULL_AUTHTOK : 0);
228 if (pam_retval == PAM_SUCCESS) {
229 debug("PAM Password authentication accepted for "
230 "user \"%.100s\"", pw->pw_name);
233 debug("PAM Password authentication for \"%.100s\" "
234 "failed[%d]: %s", pw->pw_name, pam_retval,
235 PAM_STRERROR(__pamh, pam_retval));
240 /* Do account management using PAM */
241 int do_pam_account(char *username, char *remote_user)
245 do_pam_set_conv(&conv);
248 debug("PAM setting ruser to \"%.200s\"", remote_user);
249 pam_retval = pam_set_item(__pamh, PAM_RUSER, remote_user);
250 if (pam_retval != PAM_SUCCESS)
251 fatal("PAM set ruser failed[%d]: %.200s", pam_retval,
252 PAM_STRERROR(__pamh, pam_retval));
255 pam_retval = pam_acct_mgmt(__pamh, 0);
256 debug2("pam_acct_mgmt() = %d", pam_retval);
257 switch (pam_retval) {
259 /* This is what we want */
262 case PAM_NEW_AUTHTOK_REQD:
263 message_cat(&__pam_msg, use_privsep ?
264 NEW_AUTHTOK_MSG_PRIVSEP : NEW_AUTHTOK_MSG);
265 /* flag that password change is necessary */
266 password_change_required = 1;
267 /* disallow other functionality for now */
268 no_port_forwarding_flag |= 2;
269 no_agent_forwarding_flag |= 2;
270 no_x11_forwarding_flag |= 2;
274 log("PAM rejected by account configuration[%d]: "
275 "%.200s", pam_retval, PAM_STRERROR(__pamh,
283 /* Do PAM-specific session initialisation */
284 void do_pam_session(char *username, const char *ttyname)
288 do_pam_set_conv(&conv);
290 if (ttyname != NULL) {
291 debug("PAM setting tty to \"%.200s\"", ttyname);
292 pam_retval = pam_set_item(__pamh, PAM_TTY, ttyname);
293 if (pam_retval != PAM_SUCCESS)
294 fatal("PAM set tty failed[%d]: %.200s",
295 pam_retval, PAM_STRERROR(__pamh, pam_retval));
298 pam_retval = pam_open_session(__pamh, 0);
299 if (pam_retval != PAM_SUCCESS)
300 fatal("PAM session setup failed[%d]: %.200s",
301 pam_retval, PAM_STRERROR(__pamh, pam_retval));
306 /* Set PAM credentials */
307 void do_pam_setcred(int init)
314 do_pam_set_conv(&conv);
316 debug("PAM establishing creds");
317 pam_retval = pam_setcred(__pamh,
318 init ? PAM_ESTABLISH_CRED : PAM_REINITIALIZE_CRED);
319 if (pam_retval != PAM_SUCCESS) {
320 if (was_authenticated)
321 fatal("PAM setcred failed[%d]: %.200s",
322 pam_retval, PAM_STRERROR(__pamh, pam_retval));
324 debug("PAM setcred failed[%d]: %.200s",
325 pam_retval, PAM_STRERROR(__pamh, pam_retval));
330 /* accessor function for file scope static variable */
331 int is_pam_password_change_required(void)
333 return password_change_required;
337 * Have user change authentication token if pam_acct_mgmt() indicated
338 * it was expired. This needs to be called after an interactive
339 * session is established and the user's pty is connected to
340 * stdin/stdout/stderr.
342 void do_pam_chauthtok(void)
346 do_pam_set_conv(&conv);
348 if (password_change_required) {
350 fatal("Password changing is currently unsupported"
351 " with privilege separation");
353 pam_retval = pam_chauthtok(__pamh, PAM_CHANGE_EXPIRED_AUTHTOK);
354 if (pam_retval != PAM_SUCCESS)
355 fatal("PAM pam_chauthtok failed[%d]: %.200s",
356 pam_retval, PAM_STRERROR(__pamh, pam_retval));
358 /* XXX: This would need to be done in the parent process,
359 * but there's currently no way to pass such request. */
360 no_port_forwarding_flag &= ~2;
361 no_agent_forwarding_flag &= ~2;
362 no_x11_forwarding_flag &= ~2;
363 if (!no_port_forwarding_flag && options.allow_tcp_forwarding)
364 channel_permit_all_opens();
369 /* Cleanly shutdown PAM */
370 void finish_pam(void)
372 do_pam_cleanup_proc(NULL);
373 fatal_remove_cleanup(&do_pam_cleanup_proc, NULL);
376 /* Start PAM authentication for specified account */
377 void start_pam(const char *user)
380 extern ServerOptions options;
381 extern u_int utmp_len;
384 debug("Starting up PAM with username \"%.200s\"", user);
386 pam_retval = pam_start(SSHD_PAM_SERVICE, user, &conv, &__pamh);
388 if (pam_retval != PAM_SUCCESS)
389 fatal("PAM initialisation failed[%d]: %.200s",
390 pam_retval, PAM_STRERROR(__pamh, pam_retval));
392 rhost = get_remote_name_or_ip(utmp_len, options.verify_reverse_mapping);
393 debug("PAM setting rhost to \"%.200s\"", rhost);
395 pam_retval = pam_set_item(__pamh, PAM_RHOST, rhost);
396 if (pam_retval != PAM_SUCCESS)
397 fatal("PAM set rhost failed[%d]: %.200s", pam_retval,
398 PAM_STRERROR(__pamh, pam_retval));
399 #ifdef PAM_TTY_KLUDGE
401 * Some PAM modules (e.g. pam_time) require a TTY to operate,
402 * and will fail in various stupid ways if they don't get one.
403 * sshd doesn't set the tty until too late in the auth process and may
404 * not even need one (for tty-less connections)
405 * Kludge: Set a fake PAM_TTY
407 pam_retval = pam_set_item(__pamh, PAM_TTY, "NODEVssh");
408 if (pam_retval != PAM_SUCCESS)
409 fatal("PAM set tty failed[%d]: %.200s",
410 pam_retval, PAM_STRERROR(__pamh, pam_retval));
411 #endif /* PAM_TTY_KLUDGE */
413 fatal_add_cleanup(&do_pam_cleanup_proc, NULL);
416 /* Return list of PAM environment strings */
417 char **fetch_pam_environment(void)
419 #ifdef HAVE_PAM_GETENVLIST
420 return(pam_getenvlist(__pamh));
421 #else /* HAVE_PAM_GETENVLIST */
423 #endif /* HAVE_PAM_GETENVLIST */
426 void free_pam_environment(char **env)
431 for (i = 0; env[i] != NULL; i++)
436 /* Print any messages that have been generated during authentication */
437 /* or account checking to stderr */
438 void print_pam_messages(void)
440 if (__pam_msg != NULL)
441 fputs(__pam_msg, stderr);
444 /* Append a message to buffer */
445 void message_cat(char **p, const char *a)
453 size_t len = strlen(*p);
455 *p = xrealloc(*p, new_len + len + 2);
458 *p = cp = xmalloc(new_len + 2);
460 memcpy(cp, a, new_len);
462 cp[new_len + 1] = '\0';